Highway Mission Creep

Last week, I wrote about the progress of the highway funding bill through Congress. A few politicians—Marco Rubio, John Kasich and Rick Santorum—don’t want to fund highways at the federal level any more, endorsing transportation devolution. I also talked about Chuck Marohn’s Strongtowns no new roads message, which has proven to have some appeal in the urbanist community.

I didn’t delve into the history of we got to the overbuilt highway system we have today. It’s a story of mission creep. President Dwight D. Eisenhower was instrumental in building the Interstate Highway System through the Federal Highway Administration (FHA). The lore goes General Eisenhower was impressed with the efficiency of German autobahn system during World War Two and sought to emulate it in the United States. The catch was Eisenhower didn’t envision plowing highways through major cities. Eric Jaffe tracked down the Eisenhower memorandum detailing his chagrin at highways steamrolling through cities in this City Lab article.

Eisenhower obviously was naive in not anticipating that once he fully unleashed the highway industrial complex, its appetite would grow, and it would set its sights on urban areas. Eisenhower went on to compound his naivete with aloofness while the FHA bulldozed through cities under his nose during his eight years in office. Much like his warning about the military industrial complex, Eisenhower’s warning about the highway industrial complex seems futile, like Dr. Jekyll saying on his way out the door: by the way I’ve created a monster, good luck with that.

Andy Singer pokes fun at endless highway expansion in this cartoon from his book “Why We Drive.” (Andy Singer)

Once the Interstate System was set in motion, the FHA eventually did pave highways through almost every major American city, cementing suburban sprawl growth patterns and hollowing out and sapping the vitality out of vibrant urban neighborhoods. Jaffe estimated 335,000 homes were razed in the first decade of Interstate highway construction alone. Throughout its history, interstates have displaced millions of Americans. Highway planners disproportionately chose to level and pave over neighborhoods with large minority populations. In many cities, they bisected thriving black neighborhoods, hastening their decline and depressing property values.

Redlining and urban highway construction were a one-two punch that did much to impoverish black communities, proving racial oppression wasn’t just a lingering legacy of slavery but also an active ongoing process that continued to tighten the screws on black Americans. Every American generation has found a way to put its own signature on the ongoing saga of racial oppression—segregation, discriminatory voting laws, discriminatory urban “renewal,” neglected urban schools, racial profiling and police brutality—and intermittently pay attention long enough to make some progress.

They may have chosen to level minority communities, but, at least in part, highway engineers’ intentions were good in building urban highways. Speeding interstate travel and making intercity trips more convenient is a noble goal; however, highway expansion in urban areas proved to be misguided. Congestion persisted even as cities sacrificed more and more neighborhoods—and the tax bases along with them—to the chopping block for highways. Each new highway promised to reduce congestion and commute times, but almost universally the promise rang hollow. More highways begat more traffic congestion.

This map shows the havoc that the I-94/I-35 interchange wreaked on Minneapolis. A few dozen city blocks were blasted off the map and paved. In total, Singer estimates freeway construction cost Minneapolis at least 52 million dollars per year in lost property tax revenue. (MnDoT)

In 1968, mathematician Dietrich Braess formulated what became known as Braess’ paradox: in a congested road network, the addition of a new route will increase overall travel times. Seattle Urban Mobility Plan said the paradox can also be expressed as “the theory that direct routes often function as bottlenecks, and so reductions in total capacity can reduce congestion.” Cities have seen results that support the conclusion. Seoul saw traffic volumes decrease and property values go way up after it demolished Cheonggye Expressway, its downtown highway viaduct, and replaced it with a linear park. Stuttgart, San Francisco, Portland, New York, and Milwaukee have seen similar results when tearing down urban freeways.

Recently, Amherst professor Anna Nigurney argued the Braess paradox stops applying at sufficiently high congestion levels and a new route will have no effect on travel times, which is almost as damning and undercuts the justification for expanding urban highway infrastructure. Nigurney’s findings bolster the case against highway expansion, as Lisa Zyga explains:

In a sense, the negation of the paradox actually adds to the paradox’s original conclusions: when designing transportation networks (and other kinds of networks), extreme caution should be used in adding new routes, since at worst the new routes will slow travelers down, and at best, the new routes won’t even be used.

This academic view of highways has yet to enter the mainstream. Generally the public is very supportive of infrastructure spending. It sounds wholesome. PBS’s slant is pretty clear from this article’s title alone: The Highway Trust Fund keeps bridges from falling down, but will Congress reauthorize it? The Maddowblog couldn’t help but lambaste Republican presidential candidates for not wanting to invest in infrastructure at the federal level. It’s worth criticizing the Republican plans since cutting transit funding, an explicit goal in most GOP plans, is a bad, dangerous idea. However, to not criticize the transportation status quo is to overlook how state and federal Departments of Transportation are saddling us with an ever-growing portfolio of highways of dubious value and a massive maintenance backlog that is coming due.

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Doug Trumm is The Urbanist's Publication Director. He moved to Seattle from Minnesota in 2014 and recently graduated from the Evans School of Public Policy and Governance at UW. He lives in East Fremont/West Wallingford and loves to explore the city on his bike.

Isn’t most of these problems related to the fact that we do not have market-based road pricing? It might encourage the drivers to take into account the influence of their decision on the others… Also, if the rationale of the real estate tax is to encourage the most economically beneficial land use, shouldn’t then also the roads (road users) pay land tax? I am though afraid that this pulls the externality internalization too far, and we should also start internalizing the positive ones, and this may rapidly get too complex for any real application. But one can still imagine…

Another note: I don’t know what do exactly you mean as “traffic congestion”. Travel time (across different transport modes) is a better indicator: short trip on congested street may be preferable to a long one on empty roads. But here I am ignoring psychology…

I’m for reforming the way we pay for highways. I don’t know about the feasibility of implementing a land-tax on road users, but maybe congestion pricing in the central business district like London, Milan, Stockholm have implemented would both generate transportation funds and decrease traffic volumes at peak times.

As to traffic congestion versus travel times, I see you point, but I don’t think this is what the Braess effect says. The Braess Effect says counter-intuitively in a malfunctioning congested road system overall journey time will increase with the addition of a direct route and could decrease with the removal of a direct route. The Seattle Urban Mobility Plan did use the word congestion instead, but then Seattle then ended up building a SR-99 car tunnel (disregarding the Braess effect) so that may shed some light on why they expressed a muted version of the theory. Of course there is also an argument that Seattle geography is already too bottleneck-y so the network couldn’t take some of the SR-99 traffic spilling over to city streets and I-5. I don’t really buy it, especially not when keeping that route cost billions of dollars that could have been put to better use.

I suspect Braess effect only applies to certain networks/traffic loads, and may not be true for SR99. But I have no evidence.

But expanding or not expanding the roads–congestion charging makes sense anyway. If it creates enough revenues for expansion, then one may argue that the expansion is actually worth it. Currently we simply do not have the data. Increased travel times is a measure, but that does not tell how much that is worth in terms of money. And we need the monetary equivalent as construction must be paid by $$ and not with gained time…

If the road system is congested in a system with a single bottleneck, creating a bypass for the bottleneck may actually work. If it’s congested in a system with a robust road grid, building more is definitely not going to help.

Seattle does not really have tight bottlenecks, unless you’re travelling *east-west* across Lake Washington or the Duwamish.

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